3.
DERVIE/ISWC 2013, 21st October, Sydney
Motivation
RFID/Barcodes enable the capture of the identity and
location of physical items and goods as they move along
the supply chain.
The Electronic Product Code(EPC) provides products with
identities.
The Electronic Product Code Information Service (EPCIS)*
provides a set of speciﬁcations for the syntactic capture
and informal semantic interpretation of EPC based product
information.
*http://www.gs1.org/gsmp/kc/epcglobal/epcis
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

4.
DERVIE/ISWC 2013, 21st October, Sydney
Motivation
Supply chain product information sharing limitations
Large volumes of traceability data are recorded at each
partner’s end. While the datasets are inherently related,
the underlying schemas and data storage mechanisms
employed render the datasets disconnected.
The EPCIS XML schemas deﬁne only the structure of the
event data to be recorded. The semantics of event data
and data curation processes are informally deﬁned in the
speciﬁcation.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

6.
DERVIE/ISWC 2013, 21st October, Sydney
Declarative representative of EPCIS events
EEM: EPCIS Event Model
EEM based linked datasets can be exploited in order to
improve visibility, accuracy and automation along the
supply chain.
EEM can be used to derive implicit knowledge that can
expose inefﬁciencies such as shipment delay, inventory
shrinkage and out-of-stock situation.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

7.
DERVIE/ISWC 2013, 21st October, Sydney
What is an EPC?
Electronic Product Code
A universal identiﬁer that gives a unique, serialised identity
to a speciﬁc physical object.
Encoded on data carriers: Active/Passive RFID tags,
Barcodes, Human Readable Number and more.
Can be used to track all kinds of objects: trade items, ﬁxed
assets, documents, or reusable transport items.
While barcodes are commonly used to distinguish a can of
soup from a box of chocolate chip biscuits, the EPC can
identify a speciﬁc can of soup or box of biscuits.
“Next Generation Barcode”.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

12.
DERVIE/ISWC 2013, 21st October, Sydney
Examples: EPCIS events
“At time T, the association of the following case tags to the
following pallet tag was created at palletizer #3, to fulﬁll
order #1234”.
“Between the time the case crossed the ﬁrst beam and the
second beam at location L, the following tag was read”.
“At Time T, Object X was observed at Location L.”.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

13.
DERVIE/ISWC 2013, 21st October, Sydney
EPCIS Events: An informal Intuition
One generic and four speciﬁc physical event types
EPCISEvent: the generic EPCIS event.
ObjectEvent: an event that occurred as a result of some
action on one or more entities denoted by EPCs.
“This list of objects was observed entering DC #9 at
10:01AM, during Receiving”.
AggregationEvent: an event that happened to one or more
EPC-denoted entities that are physically aggregated.
“This list of objects was just Palletized with this Pallet ID at
Palletizer #27 at 12:32PM”.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

14.
DERVIE/ISWC 2013, 21st October, Sydney
EPCIS Events: An informal Intuition
One generic and four speciﬁc physical event types.
QuantityEvent: an event concerned with a speciﬁc number
of objects all having the same type, but where the
individual instances are not identiﬁed.
“There were 200 bottles of Brand X cola in store #4123
backroom at 3:20PM”.
TransactionEvent: an event in which one or more entities
denoted by EPCs become associated or disassociated
with one or more identiﬁed business transactions.
“Order #123 was fulﬁlled with objects x, y and z”.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

16.
DERVIE/ISWC 2013, 21st October, Sydney
EEM: The EPCIS Event Model
A domain speciﬁc, ontological information/data model.
Restricts the entities, relationship and attributes to a large
subset of the EPCIS speciﬁcation.
Deﬁnes conceptual primitives with the appropriate level of
semantic abstraction required to model the various kinds of
EPCIS events that can be raised and the four information
dimensions they encapsulate.
Focuses on a tight conformance with the EPCIS standard
and Simplicity.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

17.
DERVIE/ISWC 2013, 21st October, Sydney
EEM: Modelling Decisions
Level of Expressivity
Most data models for the Web of data are designed with
relatively weak semantics to facilitate integration.
We wanted a model that could constrain the formal
interpretation of EPCIS events to align with the informal
intuition given by the standard.
The model should have the appropriate level of formality
needed to enforce the desired consequences.
EEM has been represented in the OWL DL proﬁle, with
plans to reﬁne it to OWL QL/RL to fcailitate querying and
rule based reasoning.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

18.
DERVIE/ISWC 2013, 21st October, Sydney
EEM: Modelling Decisions
Relationship with the Event entity in other event model
For the ﬁrst version, we deliberately avoid a mapping of the
EEM event entity with event related entities in other
models.
EEM addresses the need of knowledge representation for
a very speciﬁc class of events.
The requirements, motivation and viewpoints behind the
design of EEM are orthogonal to those presented by other
event models.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

19.
DERVIE/ISWC 2013, 21st October, Sydney
EEM: Modelling Decisions
Extensibility
The EPCIS standard allows extensibility of event types and
event attributes.
Being an ontological model, designed with modularity as
one of its inherent strengths, EEM provides the ﬂexibility
required to add new entities, attributes and relationships.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

20.
DERVIE/ISWC 2013, 21st October, Sydney
Modelling Decisions: Concrete Implications
Existential property restrictions
An ObjectEvent is required to have associated EPCs, an
action type and the time of event.
A QuantityEvent is required to have an EPCClass
associated with it.
Functional properties
An event occurs at a unique location, it has a unique action
type and is part of a singular business process.
Semantics of Action
EEM encodes the informal semantics by deﬁning SWRL
rules over event types and action attribute values.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

28.
DERVIE/ISWC 2013, 21st October, Sydney
Modelling the Semantics of “Action”
An event ﬁeld deﬁned for Object, Aggregation and
Transaction events
Action: an activity that has taken place on the object(s)
during the business step that generated the event.
Values (individuals in EEM): ADD, OBSERVE and DELETE.
ADD: The entity has been created or added to
(commissioned).
OBSERVE: The entity has not been changed.
DELETE: The entity has been removed from or destroyed
altogether.
hasActionType relates an event to the action type.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

29.
DERVIE/ISWC 2013, 21st October, Sydney
Modelling the Semantics of Action
For an ObjectEvent what are the informal semantics of the
ADD action type ?
Object Event: Informal semantics of ADD
“EPC(s) named in the event have been commissioned as part
of this event”.
SWRL Rule encoding the informal semantics
ObjectEvent(?e), actionType(?e, ADD), associatedWithEPCList(?e, ?list),
hasBusinessStepType(?e, commissioning)
→ commissioned(?e, ?list)
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

30.
DERVIE/ISWC 2013, 21st October, Sydney
Implementing EEM: LinkedEPCIS library
EEM is a complex data model.
Non trivial to generate class assertions and complex
queries without knowing the structure of the model and
nomenclature of the entities.
LinkedEPCIS* - an open source Java API to,
Encourage the uptake of EEM among EPCIS conforming
organisations and industries
Ease the creation of EEM instances
Facilitate querying over the instantiated datasets
* http://code.google.com/p/linked-epcis/
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

34.
DERVIE/ISWC 2013, 21st October, Sydney
Agri-food scenario
The tomatoes are packaged and shipped to downstream
traders.
The packaging of tomatoes is done in crates, each of which
is tagged with an RFID chip that carries an EPC(SGTIN).
Sensors installed at the packaging unit register the EPCs
of the crates as they are being packed.
Every read is recorded and registered as an EPCIS event
type based on the business process, the location and the
supply chain operation.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data

38.
DERVIE/ISWC 2013, 21st October, Sydney
Conclusions
The representation of EPCIS events on the Web of data is
an important step towards achieving the objectives of,
sharing traceability information
detecting inconsistencies
EEM provides the ontological primitives required to
represent EPCIS events using Semantic Web standards
on the Web of data.
The capture, storage and querying of EPCIS events linked
datasets is realised using the LinkedEPCIS library, which
can be integrated with existing RFID and EPCIS
implementations.
EEM and the LinkedEPCIS library has been exempliﬁed by
modelling and curating events from the agri-food supply
chain.
m.solanki@aston.ac.uk
Representing Supply Chain Events on the Web of Data